Comparative studies on the physiology and on the energy-yielding metabolism of anaerobic and facultatively anaerobic spirochetes will be conducted. Host-associated as well as free-living forms will be investigated. For these studies, spirochetes will be isolated from diverse natural environments. The pathways of amino acid fermentation in Treponema denticola and in other spirochetes will be investigated. Other areas of investigation: chemotaxis and motility of spirochetes; physiological significance of spirochetal spherical bodies; the nature of the specific requirement for Na plus and C1 minus by Spirochaeta litoralis; isolation and study of a bacteriophage or bdellovibrio capable of lysing spirochetes; the chemical structure of cell wall layers and of the outer sheath (outer cell envelope) of spirochetes.